Add PEP 291 for backward compatibility

pep-0000.txt

@@ -93,6 +93,7 @@ Index by Category
  S   284  Integer for-loops                            Eppstein, Ewing
  S   286  Enhanced Argument Tuples                     von Loewis
  S   287  reStructuredText Standard Docstring Format   Goodger
+ I   291  Backward Compatibility for Standard Library  Norwitz
 
  Finished PEPs (done, implemented in CVS)
 
@@ -267,6 +268,7 @@ Numerical Index
  S   287  reStructuredText Standard Docstring Format   Goodger
  SD  288  Generators Attributes and Exceptions         Hettinger
  SR  289  Generator Comprehensions                     Hettinger
+ I   291  Backward Compatibility for Standard Library  Norwitz
  SR  666  Reject Foolish Indentation                   Creighton
 
 
@@ -314,6 +316,7 @@ Owners
     Mick, Trent              trentm@activestate.com
     Montanaro, Skip          skip@pobox.com
     Moore, Paul              gustav@morpheus.demon.co.uk
+    Norwitz, Neal            neal@metaslash.com
     Oliphant, Travis         oliphant@ee.byu.edu
     Pelletier, Michel        michel@digicool.com
     Peters, Tim              tim@digicool.com

pep-291.txt

@@ -0,0 +1,92 @@
+PEP: 291
+Title: Backward Compatibility for Standard Library
+Version: $Revision$
+Last-Modified: $Date$
+Author: neal@metaslash.com (Neal Norwitz)
+Status: Active
+Type: Informational
+Created: 06-Jun-2002
+Post-History:
+Python-Version: 2.3
+
+
+Abstract
+
+    This PEP describes the packages and modules in the standard
+    library which should remain backward compatible with previous
+    versions of Python.
+
+
+Rationale
+
+    Authors have various reasons why packages and modules should
+    continue to work with previous versions of Python.  In order to
+    maintain backward compatibility for these modules while moving the
+    rest of the standard library forward, it is necessary to know
+    which modules can be modified and which should use old and
+    possibly deprecated features.
+
+    Generally, authors should attempt to keep changes backward
+    compatible with the previous released version of Python in order
+    to make bug fixes easier to backport.
+
+
+Features to Avoid
+
+    The following list contains common features to avoid in order
+    to maintain backward compatibility with each version of Python.
+    This list is not complete!  It is only meant as a general guide.
+
+    Note the features to avoid were implemented in the following
+    version.  For example, features listed next to 1.5.2 were
+    implemented in 2.0.
+
+        Version    Features
+        -------    --------
+          1.5.2    string methods, Unicode, list comprehensions, 
+                   augmented assignment (eg, +=), zip(), import x as y,
+                   dict.setdefault(), print >> f, calling f(*args, **kw),
+                   plus 2.0 features
+
+          2.0      nested scopes, rich comparisons, function attributes,
+                   plus 2.1 features
+
+          2.1      use of object or new-style classes, iterators, 
+                   using generators, nested scopes, or //
+                   without from __future__ import ... statement,
+                   plus 2.2 features
+
+          2.2      bool, True, False, basestring, enumerate(), {}.pop(),
+                   PendingDeprecationWarning, Universal Newlines,
+                   plus 2.3 features
+
+
+Backward Compatible Packages, Modules, and Tools
+
+    Package/Module     Maintainer(s)          Python Version
+    --------------     -------------          --------------
+    compiler           Jeremy Hylton               2.1
+    distutils          Andrew Kuchling             1.5.2
+    email              Barry Warsaw                2.1
+    sre                Fredrik Lundh               1.5.2
+    xml (PyXML)        Martin v. Loewis            2.0
+    xmlrpclib          Fredrik Lundh               1.5.2
+
+
+    Tool                         Maintainer(s)   Python Version
+    ----                         -------------   --------------
+    scripts/freeze/modulefinder  Thomas Heller       1.5.2
+
+
+Copyright
+
+    This document has been placed in the public domain.
+
+
+
+Local Variables:
+mode: indented-text
+indent-tabs-mode: nil
+sentence-end-double-space: t
+fill-column: 70
+End: